<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>1_引出生命周期</title>
</head>
<body>
	<!-- 准备好一个“容器” -->
	<div id="test"></div>
	
	<!-- 引入react核心库 -->
	<script type="text/javascript" src="../js/react.development.js"></script>
	<!-- 引入react-dom，用于支持react操作DOM -->
	<script type="text/javascript" src="../js/react-dom.development.js"></script>
	<!-- 引入babel，用于将jsx转为js -->
	<script type="text/javascript" src="../js/babel.min.js"></script>

	<script type="text/babel">
        class Life extends React.Component{
            state = {opacity: 1}

            death = (e) => {
                // 卸载组件
                ReactDOM.unmountComponentAtNode(document.getElementById('test'))
            }

            // 组件挂载完毕
            componentDidMount(){
                console.log("componenetDidMount");


                this.timer = setInterval(() => {
                    // 获取原状态
                    let {opacity} = this.state
                    // 减小0.1
                    opacity -= 0.1
                    if(opacity < 0) opacity = 1
                    // 设置新的透明度
                    this.setState({opacity: opacity})

                }, 200)
            }

            // 组件将要卸载
            componentWillUnmount(){
                // 清楚定时器
                clearInterval(this.timer)
            }
            
            render(){
                return (
                    <div>
                        <h2 style={{opacity: this.state.opacity}}>React学不会怎么办？</h2>
                        <button onClick={this.death}>不活了</button>
                    </div>
                )
            }
        }
        ReactDOM.render(<Life />, document.getElementById('test'))
	</script>
</body>
</html>